Android 测量字符宽度的几种方法和场景

gistfile1.java

mTextView.setTextSize(TypedValue.COMPLEX_UNIT_SP, 14);
TextPaint textPaint = mTextView.getPaint();
String source = "Lorem ipsum dolor sit amet";

// mTextView的宽度作为参考值
mTextView.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

    @Override
    public void onGlobalLayout() {
        int textViewWidth = mTextView.getMeasuredWidth();
    }
});



/*----纯字符串测量----*/
mTextView.setText(source);

// 1. measureText
float measureTextWidth = textPaint.measureText(source);

// 2. getTextBounds
Rect rect = new Rect();
textPaint.getTextBounds(source, 0, source.length(), rect);
float rectWidth = rect.width();

// 3. Layout.getDesiredWidth
float desiredWidth = Layout.getDesiredWidth(source, textPaint);

/////////////////////////////////////
//  1. measureTextWidth = 348.0    //
//  2. rectWidth        = 346.0    //
//  3. desiredWidth     = 347.7422 //
//  参考值:                         //
//  textViewWidth       = 348      //
/////////////////////////////////////



/*----包含Spanned字符测量----*/
SpannableString sourceSpannable = new SpannableString(source);
sourceSpannable.setSpan(new RelativeSizeSpan(1.5F), 2, 4, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
mTextView.setText(sourceSpannable);

// 1. measureText 不适用
// 2. getTextBounds 不适用
// 3. Layout.getDesiredWidth 可以测量CharSequence
float spanDesiredWidth = Layout.getDesiredWidth(sourceSpannable, textPaint);

/////////////////////////////////////
//  spanDesiredWidth  = 359.61328  //
//  参考值:                         //
//  textViewWidth     = 360        //
/////////////////////////////////////



/*----TextPaint自定义后字符测量----*/

textPaint.setFakeBoldText(true);    //加粗
textPaint.setTextSkewX(-0.5F);      //斜体
mTextView.setText(source);

// 1. measureText
float paintMeasureTextWidth = textPaint.measureText(source);

// 2. getTextBounds
Rect paintRect = new Rect();
textPaint.getTextBounds(source, 0, source.length(), paintRect);
float paintRectWidth = paintRect.width();

// 3. Layout.getDesiredWidth
float paintDesiredWidth = Layout.getDesiredWidth(source, textPaint);

//////////////////////////////////////////
//  1. paintMeasureTextWidth = 344.0    //
//  2. paintRectWidth        = 351.0    //
//  3. paintDesiredWidth     = 343.71094//
//  参考值:                              //
//  textViewWidth            = 344      //
//////////////////////////////////////////